<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>土豆</title>
		<style type="text/css">
			.todou {
				position: relative;
				margin: 30px auto;
				width: 520px;
				height: 280px;

			}

			.todou .img {
				width: 100%;
				height: 100%;
			}

			 .mask {
				position: absolute;
				top: 0;
				left: 0;
				display: none;
				width: 100%;
				height: 100%;
				background: rgba(0,0,0,0.3) url(imgs/bofang.png) no-repeat center;
			} 
			.todou:hover .mask{
				display: block;
			}
		</style>
	</head>
	<body>
		<div class="todou">
			<div class="mask"></div>
			<img src="imgs/Taobao.jpg">
		</div>
	</body>
</html>
